The background description provided herein is for the purpose of generally presenting the context of the present invention. The subject matter discussed in the background of the invention section should not be assumed to be prior art merely as a result of its mention in the background of the invention section. Similarly, a problem mentioned in the background of the invention section or associated with the subject matter of the background of the invention section should not be assumed to have been previously recognized in the prior art. The subject matter in the background of the invention section merely represents different approaches, which in and of themselves may also be inventions. Work of the presently named inventors, to the extent it is described in the background of the invention section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present invention.
In current power industry, cheap, long-lasting ways are required to store the excess energy produced by power plants. The energy can be stored in the form of intermittent power from renewable and cleaner energy sources, such as solar and wind farms. Unfortunately, the batteries available for grid-level storage are either too expensive or lack of thousands of cycles needed to make them cost-effective.
Lead-acid battery is one of the secondary batteries or rechargeable batteries. However, the lead-acid battery has the problems of, such as, significant negative impact on the environment, sulfation, low density and low cycle life.
Recent advances in battery development have promoted lithium iron phosphate (LFP) technology. With its high thermal stability, LFP is suitable for high-rate charge-discharge applications in both vehicles and power tools.
Another alternative battery option is the aqueous electrolyte battery such as aqueous sodium/potassium battery, which is environment friendly and can be fabricated in simple way. Aqueous system batteries have significantly higher rate than non-aqueous electrolyte system batteries due to the high conductivity of the aqueous system. Comparing with the non-aqueous electrolyte system, which requires a much more complicated design with high surface area current collectors, very thin roll-coated electrodes, and a large-area polymer separator, the aqueous electrolyte allows for use of much thicker electrode, much less expensive separator and current collector materials. Additionally, the aqueous system can be assembled in an open-air environment instead of a moisture-free fabrication environment which is required by non-aqueous system, resulting in a significantly low cost for producing the aqueous system. The advantages of using aqueous system lie in that compounds of abundant elements such as sodium compounds are used in electrode materials and electrolytes to replace the compounds of lithium. Further, water is used in electrolyte in the aqueous system to replace the expensive non-aqueous solvent. Sodium/potassium aqueous battery technology may be a prominent device to replace the lead-acid battery. The lower energy density of the aqueous battery is an acceptable trade-off for lower cost, longer cycle life, less hazardous battery chemistry and no significant negative impact to the environment because it contains no hazardous materials, no corrosive acids, no noxious fumes.
Therefore, a heretofore unaddressed need exists in the battery industry to provide simple and cost effective manufacturing process for producing electrode active materials.